Abstract: The similarity problem, existing in the simulation tests for bearing capacity of pile foundation, is studied. The emphasis is on the following three major aspects such as the similarity of the environments between test and engineering pile, the similarity between shearing friction test and the side friction force of engineering pile and the similarity between the triaxial test and endbearing capacity of pile. The study shows that in the simulation test the samples should be undisturbed and the state of the stress in test should be consistent to that of the engineering for the test of pile side friction in the simulation test. For endbearing capacity of pile, the samples should be undisturbed, but the confining pressure of samples is shrank according to geometry similarity constant, so as to obtain the practical endbearing capacity of pile by multiplying the test results.

Key words: similarity, bearing capacity of pile foundation, simulation test